Clinicians are finding that sedation, although often necessary, may be putting their patients in harm’s way.

By Brendan Lillie, BS, RRT-NPS


Heavy sedation is harmful and can increase mortality, but unfortunately, sedation during mechanical ventilation is often necessary. This article is not going to give readers tables of medications and the associated dosages, time to onset, and adverse effects. Instead, it will focus on the deleterious effects of oversedation and prolonged, uninterrupted sedation.

The use of sedation was first demonstrated at Massachusetts General Hospital in 1846, using ether as an anesthetic during surgery. Over the last 166 years, advances in medical knowledge coupled with pharmaceutical technologies have given rise to an era where there is a drug for almost any condition or disease. Mechanical ventilation is no exception. Drugs are often needed to help facilitate endotracheal intubation and, afterwards, to keep the patient comfortable and synchronous with the ventilator. There is currently no standard or nationally accepted objective method to assess the adequacy of sedation in the intubated patient,1 and many patients show signs of inadequate sedation post-intubation.2

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Providing sedation, analgesia, and even paralysis is sometimes necessary to achieve quality care for the mechanically ventilated patient. Working directly with the physician and nurse, respiratory therapists must have a basic knowledge of each drug’s dose, hemodynamic effects, and side effects. But new evidence is demonstrating that prolonged heavy sedation and delirium of the mechanically ventilated patient can be detrimental on a physical and cognitive level. It is now imperative that during an acute, emergent episode, we as healthcare professionals consider the chronic, long-term needs of the patient.

Sedation

Proper sedation during mechanical ventilation is key to having the best possible outcome for the patient. The feeling of an endotracheal tube can be extremely unpleasant and a direct source of anxiety to some patients. Other patients become dyssynchronous with the ventilator as they feel a positive pressure breath being delivered. These, along with many other factors, can lead to the need for sedation during mechanical ventilation. There are always associated sequelae with sedation and analgesia, including respiratory depression, hemodynamic instability, renal failure, and deconditioning.3 Because of these adverse events, patients should be given the least amount of sedation possible to keep them comfortable. Some of the side effects of heavy sedation include:

  • Hemodynamic instability
  • Cough suppression
  • Varying Vt
  • Inhibition of normal patient movement
  • Aspiration
  • Accelerated deconditioning
  • Prolonged time on mechanical ventilation
  • Promotes posttraumatic stress disorder

Sedatives and analgesics play an important role in patient comfort and are routinely administered to reduce pain and anxiety,4 but these medications can have detrimental effects. For instance, continuous intravenous sedation is associated with prolonged mechanical ventilation as compared with sedation via intermittent boluses. Co-sedation with a benzodiazepine and opioid by constant infusion provides more reliable sedation and is easier to titrate than a benzodiazepine alone, without significant difference in the rate of adverse events.5

Every patient receiving mechanical ventilation should be given a daily spontaneous awakening trial (SAT).6 By turning off the sedation/analgesia that a patient is receiving, there is a marked reduction in days on mechanical ventilation, as well as increasing the likelihood of extubation.7 The SAT should be done in coordination with a spontaneous breathing trial (SBT) in order to achieve the best results.6,8


Delirium

Over the past five to seven years, new research has proven that heavy sedation can lead to delirium, and for all the benefits of sedation, the damage caused by unrecognized delirium has resulted in a threefold increase in 6-month mortality compared to patients without delirium.4,9 Each additional day a patient is in delirium, there is a 10% increased risk of death.4 Sedation is proving to be as detrimental to a patient’s long-term health as it is helpful during mechanical ventilation.10 Delirium occurs in 60% to 80% of patients receiving mechanical ventilation,4,7 and patients in delirium have been shown to have longer hospital stays, leading to an increase in healthcare costs of as much as $10,000 to $15,000.4,7,9,11 Using a benzodiazepine-opioid or a diprivan-opioid combination of medications5 or sedative agents that are GABA-receptor sparing, such as dexmedetomidine, a novel alpha-2 receptor agonist, as well as antipsychotic medications, has been shown to reduce the rate of delirium when compared to GABA agonist medications.4,7

Assessing the patient for delirium is key to preventing its long-term cognitive effects. The Confusion Assessment Method for the ICU (CAM-ICU),4 in conjunction with the Richmond Agitation Sedation Scale (RASS), can be extremely helpful when assessing a patient for delirium. The CAM-ICU score is an objective test in which the patient receives an order or a task to perform and must repeat or give a return demonstration of the order or task. If the patient is able to perform the order given, then they are scored at CAM-ICU negative. If they cannot perform the order given, then they are CAM-ICU positive. The CAM-ICU score should be assessed in conjunction with the RASS (Table) in order to help find the source of the patient’s delirium. The optimum goal of RASS is a 0 to –1.

Once the level of delirium has been determined, there are certain nonpharmacological ways to help treat the delirium. One way is to provide the patient with any visual or hearing aid devices that they may live with on a daily basis.9,11-13 Clinicians should have patients wear their eyeglasses or hearing aids, even if they appear to be unconscious, because if they awaken or come to for even a short time, having their sight and hearing abilities will help relieve delirium. Other ways to help is to have a clock and a board with the current date on it directly in the patient’s line of sight.9,11,12 Patients should be constantly reminded of the date and time to help orient them. They also should be reintroduced to a normal sleeping routine,9,11,12 and should be awake during daytime hours and sleep at night. The patients’ rooms should be as dark and as quiet as possible at night.

Early Mobility

After a patient’s sedation/analgesia and mechanical ventilation have been minimized, the next step is adding physical activity. This must involve an interdisciplinary team that includes physical therapy, nursing, and respiratory therapy. The physical therapist should assess the patient’s physical ability to participate, a nurse should assess physiologic stability, and a respiratory therapist will maintain the patient’s airway.3 Also, a critical care physician should confirm that there are no contraindications to physical activity.3,4 Physical activity can be as simple as having a patient sit on the edge of the bed with his legs dangling over the side, or as complicated as having the patient ambulate. The multidisciplinary team should ensure that any artificial airway or invasive IV or catheter is sufficiently cared for, which will significantly reduce the risk of a life-threatening event during physical activity. Adverse events occur in approximately 9% of patients receiving early mobility.8 Indications for stopping early mobility include10:

  • Hypo/hypertension
  • Prolonged bradycardia or tachycardia
  • Prolonged bradypnea or tachypnea
  • Refractory hypoxemia
  • Ventilatory dyssynchrony
  • New onset arrhythmia
  • Airway emergency
  • Patient collapse

Mechanical Ventilation

Keeping a patient comfortable while receiving mechanical ventilation can be a daunting task. Between the routine nursing care, hemodynamic monitoring, airway management, daily x-rays, or whatever else may be involved, mechanically ventilated patients require a great deal of work—now even more so given our knowledge of the detrimental long-term effects of sedation and analgesia. Any patient who has any spontaneous respiratory effort should be placed on a spontaneous mode of mechanical ventilation. No patient should be sedated for any extended period of time to the point where they cannot trigger the ventilator. When the patient can trigger the ventilator, he should immediately be given a spontaneous breathing trial, whether with pressure support ventilation, T-piece, or per individual unit protocol.

It is demonstrated that respiratory therapy-driven weaning protocols that include a daily SBT significantly shorten time to extubation when compared to physician-driven weaning.3 In conjunction with this, a daily interruption of sedation/analgesia should be administered until the patient can follow commands or becomes agitated.3 The SBT should be done in coordination with the patient’s spontaneous awakening trial. If the patient is stable while breathing spontaneously, is hemodynamically stable off sedation, and is not in delirium, then the patient should be extubated.

ABCDE Bundle

The collaborative effort of delirium prevention can be “bundled” up into what is know as the ABCDE bundle.10 The bundle consists of Awakening and Breathing Coordination, Delirium monitoring and management, and Early mobility. The overall goals of the ABCDE bundle are:

  • Improve collaboration among team members
  • Create a standardized care process
  • Break the cycle of oversedation and prolonged mechanical ventilation

Utilization of the ABCDE bundle must be through collaboration of the respiratory therapist, nurse, physical therapist, and physician. If any one of those team members is not included, then the ABCDE bundle will not be executed to its fullest potential.

Conclusion

Ventilator management is changing. Oversedation is now a direct contradiction to the Hippocratic oath. By not oversedating patients, we can decrease the duration of mechanical ventilation, decrease the number of patients in delirium, and increase early discharge. With a multidisciplinary effort, the culture of heavily sedating our patients can come to an end.

RT

Brendan Lillie, BS, RRT-NPS, is a staff respiratory therapist at Newton-Wellesley Hospital in Newton, Mass. For further information, contact [email protected].


References

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  3. Ruokonen E, Parviainen I, Jakob M, et al. Dexmedetomidine versus propofol/midazolam for long-term sedation during mechanical ventilation. Intensive Care Med. 2009;35:282-90.
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  11. Vanderbilt University Medical Center. Outcomes and reports of ICU patients. 2011. Available at: www.mc.vanderbilt.edu/icudelirium/outcomes.html Accessed May 15, 2012.
  12. Vanderbilt University Medical Center. Delirium overview and how to diagnose it. 2011. Available at: www.mc.vanderbilt.edu/icudelirium/overview.html Accessed May 15, 2012.
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